Not exactly airplanes or surface vehicles, this type of hovering aircraft is a pretty interesting niche.
The Ground Effect Vehicle (GEV) was first envisioned in the 1920s. Riding on cushions of air and hovering just above a flat surface, the aircraft type is currently on the rise once more (no pun intended). If you've ever wanted to know more about them, here's how Ground Effect Vehicles work.
What Is Ground Effect?
Ground effect is the result of the relationship between a lifting wing and fixed surface located beneath it. As air is directed downwards and pressurized by the wing, the fixed surface acts as a boundary which traps the air. The result of this is a ‘cushion’ of air.
The ground effect also makes it difficult or impossible for wingtip vortices to form. Typically, these vortices are bad news for the efficiency of a wing. The effect of eliminating them by use of ground effect means that there's lower induced drag. This means that an aircraft using ground effect can, in theory, travel more efficiently than if it were flying above ground effect. This is why ground effect vehicles are quite appealing.
You may have noticed ground effect when coming into land with your own RC models. It is also noticeable with RC helicopters, quads, and other multirotors.
Configurations of Ground Effect Vehicles
You can make a ground effect vehicle in a few different ways. Like with aircraft in general, there isn’t one exact configuration that all ground effect vehicles follow. You can put the wings in different places, change their shapes and plonk your engines wherever. There’s no set formula.
Alexander Lippisch, as we know, was one of the pioneers of the GEV. He came up with his own winning formula for how to build one that is still used to this day. He used a reverse delta wing in combination with a stabilizing tail wing.
There’s also the Ekranoplan Wing configuration. This was designed by Rostislav Alexeyev. It works by having the main wing in ground effect whilst another wing at the rear (which is out of ground effect) stabilizes the craft.
Taking this ‘double wing’ idea to the next level, there’s also a tandem wing style with two wings both with airfoils at the front and rear of the vehicle.
Video of Ground Effect Models
Here’s renowned aerospace designer John Schuster with some balsa wood models that explore the principles of ground effect. Maybe a GEV model could be your next RC project!
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Read more about aerodynamics
Article by James Whomsley
Editor of FliteTest.com
Contact: james@flitetest.com
YouTube Channel: www.youtube.com/projectairaviation
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